cutting fuel lines

[aquaman0001]

Looking to install secondary fuel filter before the IP. What is the most common tool and method to cut the lines? Also. is it easier to flange the lines or just clamp them?

[damork]

I removed a section of the metal fuel line where the fuel filter mounts to the frame. On mine (short body Yukon), it is just ahead of the axle where the frame becomes parallel to the ground and before a cross member. I slipped the fuel hose over the metal pipes and used hose clamps to hold it in place. Over 100k miles since the install and it works well except for corrosion problem. Word of advise if your roads are salted - grease / oil / or find a waxy undercoat spray to protect the filter head if it is aluminum. My first Racor disintegrated due to salt corrosion.

[aquaman0001]

Thanks for the tip
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[aquaman0001]

I just noticed I put that the install is before the IP, I meant the LP.....:o
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[aquaman0001]

How much fuel should I expect to come out of the lines after I cut them?
Would having the front end higher help?
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[stingthieves]

How much fuel should I expect to come out of the lines after I cut them?
Would having the front end higher help?
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LOTS..... apparently fuel will siphon by gravity at warp speed right down your arm - pass thru your arm pit and continue to travel to your socks - soaking everything along the way. My solution was to sand the fuel line nice and clean before cutting. Then armed with a 1/2 gas valve with pipe to 3/8 compression fitting on each end - I quickly cut the tube and applied the shut off valve. I was able to complete the rest of the filter installation at my leisure but added benefit is when I change the filter - I can stop the flow from the tank. I have also contemplated using the valve as a theft deterrent but I was drinking at the time! Be sure to smear a heavy coat of grease or LPS 3 over it all to keep the corrosion at bay!

[aquaman0001]

:D funny. Are the lines 3/8 or 1/2? You used a 3/8 compression fitting?
Thanks
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[rjwest]

If I remember : There is a rubber line from the metal line that goes to top of fuel tank,
squeeze it with a vise grips ( just enough to pinch it ) to prevent fuel from
siphoning,

Cut fuel line with tube cutter , if you flare the ends of the line slightly
before installing rubber fuel lines ( I used flex hose to Filter )
they will seal better...

[stingthieves]

:D funny. Are the lines 3/8 or 1/2? You used a 3/8 compression fitting?
Thanks
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it was funny - once we stepped back and looked at our selves now that it has been pointed out that with just a bit more effort - I could have pinched off the line and not taken my diesel dunking - well its even more of a grin.

Yes - 3/8 compression to 1/2 pipe - 1/2 inch pipe gas valve - 1/2 inch pipe fitting to 3/8 compression back out to a piece of line - line to the new wix filter base tee fitting on the filter base out - one branch back to stock pump - one branch to a Carter RV lift pump with a check valve back into the stock fuel line. I have a one inch vaccum sender normally open on the out put side of the pre filter - if that switch ever closes (noid lit on dash) that means I have suction and the filter is plugging. and I have a 3 psi normally open at the IP if it closes on pressure drop I need to kick in the aux pump!!!

all foolish contraptions! and stolen ideas from others here!

[aquaman0001]

Anyone know where the rubber hose to tank connection is exactly? Is it easy to access?
Thanks
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[tommac95]

Not exactly...
The general picture is the OEM linesets are steel along the frame, but transition to lined neoprene (to absorb relative movement) between frame rails and 1)powerplant , and 2) fuel tank. On my pickup, the 'rubber' lines aft for the tank are (IIRC) in the vicinity of the large diameter fill tube , ahead of the rear wheels. It would be convenient except that the location is between the rearbody sheetmetal, the frame , and the fureltank.

The 3/8" fuel feed , and 5/16" return lines accompany the brake line along the framerail.

[aquaman0001]

Filter installed. Filled filter with diesel and started right up. I let it idle for a few minutes. Went out an hour later and now it wont start. Do I have air in the lines?
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[rjwest]

YES, any time you replace the filter, run at least a quart of fuel out of the water drain...

I found the extra filter droped fuel pressure under heavy load,
added a second LP at the fuel filter, with a sw,
great for puging air after filter change,
and used at pressure boost under load.

[aquaman0001]

air leak, filter was rubbing against mounting bolt so sucking air. Fixed and running well. Considering additional pump. But looking for brand that will still allow fuel flow even if it becomes malfunctions.
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[tommac95]

your last post reminds of an original question ...
The LPs (some , anyway) use a sort of inverted flare with an oring seal ; a normal brakeline-type flare will also be accommodated by the LP female fitting.
Certain aftermarket autoparts dealers sell a short length of steel fuel line which incorporates the invert-flare-with-oring endfitting....
I employed one to incorporate a tight 180 degree bend on the auxilliary LP , as a jumper to rubber line.

[rjwest]

The OEM LP will allow fuel to be sucked through when it is not operating
(No Power) acts like a check valve,